/* * Copyright (c) 1980 Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms are permitted * provided that this notice is preserved and that due credit is given * to the University of California at Berkeley. The name of the University * may not be used to endorse or promote products derived from this * software without specific prior written permission. This software * is provided ``as is'' without express or implied warranty. */ #ifdef notdef static char sccsid[] = "@(#)popen.c 5.4 (Berkeley) 2/18/88"; #endif /* notdef */ #include <stdio.h> #include <sys/signal.h> #include <sys/types.h> #include <sys/wait.h> #include <errno.h> #define tst(a,b) (*mode == 'r'? (b) : (a)) #define RDR 0 #define WTR 1 static int popen_pid[20]; FILE * popen(cmd,mode) char *cmd; char *mode; { int p[2]; register myside, hisside, pid; if(pipe(p) < 0) return NULL; myside = tst(p[WTR], p[RDR]); hisside = tst(p[RDR], p[WTR]); if((pid = vfork()) == 0) { /* myside and hisside reverse roles in child */ close(myside); dup2(hisside, tst(0, 1)); close(hisside); execl("/bin/csh", "sh", "-c", cmd, 0); _exit(1); } if(pid == -1) return NULL; popen_pid[myside] = pid; close(hisside); return(fdopen(myside, mode)); } pclose(ptr) FILE *ptr; { register f, r; int omask; union wait status; extern int errno; f = fileno(ptr); fclose(ptr); omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); while((r = wait(&status)) != popen_pid[f] && r != -1 && errno != EINTR) ; if(r == -1) status.w_status = -1; sigsetmask(omask); return (status.w_status); }